PRACH Repetition Resource Mapping for Wider Random Access Coverage

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Solution Overview

Problem

The random access procedure in future radio communication systems, such as NR, lacks clarity, leading to potential degradation in communication throughput due to unclear relationships between PRACH repetition indices and resources.

Innovation Solution

A terminal is equipped with a control section that determines resources for multiple repetitions of a physical random access channel (PRACH) and a transmitting section that transmits these repetitions using the allocated resources, enhancing the PRACH process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple repetitions of PRACH are transmitted to improve coverage, then the coverage of random access procedure is improved, but the resource allocation becomes unclear and communication throughput may degrade

Engineering Contradiction:

Improvecoverage areaVSAvoidcommunication throughput

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent segments the PRACH transmission into multiple repetitions, each assigned to specific resources. The control section determines distinct resources for each repetition, allowing the system to expand coverage through multiple transmission attempts while maintaining clear resource allocation to prevent throughput degradation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The control section performs preliminary determination of resources for each PRACH repetition before transmission occurs. This advance planning ensures that resources are clearly allocated and managed, preventing the confusion that would otherwise lead to throughput degradation while enabling coverage improvement through multiple repetitions.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If PRACH repetitions use the same resource, then resource utilization is efficient, but the relationship between repetition indices and resources becomes unclear

Engineering Contradiction:

Improveresource utilization efficiencyVSAvoidrelationship clarity

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent applies local quality by determining resources specifically for each PRACH repetition based on its index. Instead of uniform resource allocation, the control section assigns resources with consideration for the specific repetition's position and requirements, maintaining clear local relationships while improving overall coverage.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the resource parameters for each PRACH repetition based on the repetition index. The control section determines resources dynamically, adjusting frequency, time, or other resource parameters according to the specific repetition being transmitted, thereby maintaining clear relationships between indices and resources.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20260107317A1Terminal, radio communication method, and base station

Publication Date: 2026.04.16 NTT DOCOMO INC

AI summary

A terminal according to one aspect of the present disclosure includes a control section that determines a resource for each of a plurality of repetitions of a physical random access channel (PRACH), and a transmitting section that transmits the each of the plurality of repetitions using the plurality of resources. According to one aspect of the present disclosure, coverage of a random access procedure can be improved.